Abstract WMP48: 3D MR Vessel Wall Imaging Reveals Plaque-Specific Responses to Medical Therapy in Patients With Symptomatic Intracranial Atherosclerotic Disease: Initial Experience

Introduction: Intracranial atherosclerotic disease (ICAD) is a common cause of ischemic stroke worldwide and carries a high rate of recurrence. Follow-up of symptomatic ICAD routinely relies on assessment of lumen stenosis. Magnetic resonance vessel wall imaging (MR-VWI) has recently demonstrated the potential to reliably quantify plaque features. This work presents our experience in using serial MR-VWI to quantify the morphological changes of culprit lesions in response to medical therapy in patients with symptomatic ICAD. Methods: Twenty-four patients (4 females; age 46.75±14.05 years) with acute ischemic stroke secondary to ICAD underwent baseline (1-44 days after onset) and follow-up (3-15 months after baseline) 3D whole-brain MR-VWI, which was used to acquire pre- and post-contrast images. Quantitative plaque features, including plaque volume, peak normalized wall index (pNWI), maximum wall thickness, stenosis degree, pre-contrast plaque-wall contrast ratio (CR), and post-contrast plaque enhancement ratio (ER), were derived from both baseline and follow-up MR-VWI scans. Patients with 18-month clinical follow-up were divided into progression and non-progression groups depending on whether major vascular events (stroke, TIA, death) occurred. Results: Seventeen patients were categorized into the non-progression group and 4 into the progression group. Maximum wall thickness (P=0.047), CR (P=0.020) and ER (P=0.012) showed significant decreases in the non-progression group. In the progression group, all 4 patients showed an increase in pNWI, stenosis degree and CR; plaque volume, maximum wall thickness and ER increased in three patients. Typical cases are shown in Figure. Conclusions: Quantitative assessment of lesion-specific responses to medical therapy is clinically feasible with serial MR-VWI. The changes of plaque over time may be useful for ischemic stroke risk stratification with implications for ICAD medical management.